1. Field of Invention
This invention relates to a machine which is capable of cutting a plurality of tires into elongated strips and, more specifically, such a machine which includes a cutting wheel configuration which can be readily overhauled when the cutting wheels begin to wear and the efficiency of the machine decreases.
2. Description of the Prior Art
While there exists numerous machines which will rip and shear discarded tires, they often require significant power to properly cut the tires and generate excessive heat during the cutting of the tires. Because of the heat generated, some machines include means for adding cooling water to the cutting region to prevent overheating of the cutting elements or the pieces of tire being cut.
One type of tire cutting machine, generally disclosed in U.S. Pat. Nos. 4,682,522; 4,738,172; 4,776,249; 4,802,635; 4,914,994; and 4,976,178, includes a configuration of cutting blades to segment the tire into specific parts. The cutting blades include removable sections or cutting edges which can be replaced and/or resharpened to restore the efficiency of the machine for cutting tires.
There are other tire cutting machines which appear to include rotating teeth configurations which tend to rip the tires. A plurality of overlapping cutting wheels are mounted on parallel shafts for rotation in opposite directions to also produce cutting or shearing at the overlapping edges of the cutting wheel. Such machines are generally disclosed in U.S. Pat. Nos. 4,046,324; 4,241,882; and 4,607,800; and British Patent No. 1,558,423. Some of these machines have very complicated teeth configurations and include means for replacement or resharpening of the cutting segments in order to overhaul the machine after extended use. The complicated tooth configuration of U.S. Pat. No. 4,241,882 allows cutting segments to be removed and replaced when they have become excessively worn through operation of the machine. U.S. Pat. No. 4,607,800 discloses two sets of rotating cutting wheels. The top set of cutting wheels appears to provide some ripping action for the tires or other material feed thereto. The bottom set of cutting wheels is said to primarily produce a transverse cut of the material passing therebetween. Both sets of cutting wheels include a form of replaceable wear shoe or tooth for overhauling the machine.
U.S. Pat. Nos. 4,374,573; 4,519,550; 4,684,070; and 4,684,071; and Russian Patent No. 1,333,411 disclose machines having overlapping cutting wheel configurations which are clearly intended to provide primary cutting at the side edges of the cutting wheels. Each of the machines disclosed therein appears to include a plurality of cutting and gripping plates which can be removed or replaced when excessively worn by cutting of material passing therethrough.
A similar machine, shown in U.S. Pat. No. 4,560,112, includes a plurality of cutting discs which have different thicknesses or widths in the axial direction. The cutting discs include cutting segments or teeth thereon which become worn with use. When the cutting segments are excessively worn, each segment is removed so that both side surfaces thereof can be ground to sharpen the edges. This reduces the overall thickness of the segment. The resulting narrower cutting segment can be reinstalled on the next smaller cutting wheel which has a narrower width or thickness in the axial direction. Accordingly, resharpening of the various cutting segments allows them to be progressively relocated on narrower cutting wheels with only one new set of such segments being needed for the widest cutting wheels in the array in the machine. The design of the machine in U.S. Pat. No. 4,560,112 demonstrates the need for any means which will facilitate the overhauling of such machines after extended use and wear.
The need for periodically sharpening cutting discs or wheels is also recognized in U.S. Pat. Nos. 4,052,013 and 4,134,556. The machines disclosed therein clearly employ cutting discs which overlap to provide side edge cutting of the material passing therethrough. Recognizing that the cutting discs will become dull after repeated use, these machines employed an installed grinding wheel configurations for each series of cutting wheels. The grinding wheel configuration may be used to simultaneously sharpen all the cutting wheels on the cutting wheel shaft of the series. However, each of the preferred cutting wheels disclosed therein includes a plurality of feeding teeth which are not intended to cut material directed to the machine but simply to assist in the feeding of the material to be cut at the edges of the cutting wheels. These feeding teeth must be specifically removed from the periphery of each of the cutting wheels prior to any grinding by the grinding wheel configuration.
U.S. Pat. No. 3,931,935 discloses other machines specifically adapted for cutting tires. The machines disclosed therein include two types of rotating cutting discs for cutting tires at the side edges thereof. One of the cutting discs includes circumferential cutting strips and a series of outwardly extending pegs on the outer surfaces thereof. The cutting strips and pegs must be replaced periodically in order to maintain the machine in a sharpened condition. Another cutting disc configuration employs a series of chrome strips for gripping and cutting. Again, these strips may be periodically replaced with sharpened strips in order to overhaul the cutting discs after extensive use.
The various configurations for the machines discussed hereinabove indicate a continuing concern for maintaining the cutting surfaces and edges of the cutting wheels in a condition for efficiently cutting the material passing therebetween. While replacement of or sharpening of the edges of the various cutting segments has been primarily discussed, other patents recognize the significant wear resulting from the use of such cutting wheel configurations. For example, German Offenlegungsschrift No. DE 3,413,614 includes a complicated tooth configuration and a complicated means for applying hard, wear-resistant metal to the cutting surfaces thereof.
One form of prior art paper cutting or paper shredding machine incorporates a configuration which has been employed to extend the life of the machine. For example, one type of paper shredder, sold under the registered trademark DESTROYIT, includes several models employing cutting blades having a standard thickness (for example, 1/8") and corresponding combers having a standard thickness (also about 1/8"). If the model of the paper shredder is to cut paper strips having a narrow, standard width, single cutting blades are installed on each shaft to extend between single cutting blades on the other shaft. A single standard comber is also installed between each of the cutting blades on the shaft to insure that the paper strips will be directed through the shredder.
However, if the paper is to be shredded into strips having a width which is twice the standard, a different model is employed using double cutting blades and double combers on each shaft. The two cutting blades together have a combined width which is twice the standard (in this case, 1/4"). Yet a different model could employ triple cutting blades and triple combers for cutting paper into strips having a width which is three times the standard (for example, 3/8").
It has been found that the models using such multiblade configurations could be overhauled to extend the life of the machine by rearranging the cutting blades as the cutting edges become dull. If a double blade configuration is employed, the life could be doubled by basically swapping the position of the two cutting blades on the shaft for each cutting component. If a triple cutting blade configuration is employed, the individual blades could be repositioned in order to triple the life of the machine as sharp, unused edges are positioned at the sides of the cutting components to replace the cutting edges which have become dull after extended use.
Clearly, there is a continuing concern for providing any cutting wheel configuration which is particularly adapted for refurbishing such machines after extended cutting of the tires.
Additionally, because of the need to improve the efficiency of tire cutting machines, any configuration which will facilitate the flow of material through the cutting area, reduce the friction created, and prevent undesired heating of the material and/or the cutting area is desirable. Generally, the use of rotating annular spacers between adjacent cutting wheels can be seen to urge the pieces of tire cut by the machine through the cutting section. The prior art machines disclosed in some of the patents discussed hereinabove include features which do not facilitate the most efficient flow of material through the cutting area.
For example, U.S. Pat. No. 4,519,550 includes guide fingers which are intended to move to "urge" the material through the cutting area but do not rotate to reduce the friction of the material passing therethrough. U.S. Pat. No. 4,560,121 includes a "floating" comber configuration which might facilitate the movement of the pieces through the cutting area but would generate significant heat because of friction produced by its movement within the cutting area. U.S. Pat. No. 4,046,324 includes a rotating annular spacer which would tend to urge the elongated pieces of tire through the cutting area but includes no means for preventing such pieces from rotating with the spacers to be collected at the backside of the shafts.
On the other hand, U.S. Pat. Nos. 3,931,935; 4,052,013; 4,134,556; and 4,241,882 and British Patent No. 1,558,423 disclose rotating annular spacers which include means for "stripping" or "combing" the material from the surface from the annular spacer to prevent collection at the remote side of the cutting shafts. However, not every "combing" or "stripping" means will effectively prevent the collection of pieces at the backside of the cutting shafts or insure that excessive friction is not generated by the "deflection" of pieces of tire from the rotating surface of the annular spacer.
In order to determine an effective way for preventing the collection of pieces of tire material in the cutting section of the machine without generating excessive heat, it is appropriate to analyze the types of combing means which have been employed in various types of cutting or shredding machines which may not be specifically adapted for the cutting and shredding of tires.
One group of such devices disclosed in prior art patents includes some form of combing means located at the backside of the spacer element between the cutting wheels. These spacer combers prevent the collection of pieces or strips of material between the cutting wheels at the backside thereof. Various cutting machines including such combing configurations are disclosed in U.S. Pat. No. 3,931,935; British Patent No. 1,558,423; German Patentschrift No. 249,359; German Auslegeshrift No. 1,291,606 and German Offenlegungsschrift Nos. 2,526,650; 2,723,281; 3,231,341; and 3,313,321.
All of the devices disclosed in these patents are characterized by the inclusion of some type of separate or integrally formed annular spacer ring between adjacent cutting wheels or discs on a shaft. The annular spacer ring tends to serve as a rotating comber for the aligned cutting wheel or disc on the other shaft. As a result, the pieces or strips of material are maintained in close proximity with the cutting wheel or disc by which they are formed. The spacer ring rotates in the direction of movement through the cutting area to generally facilitate the formation of the pieces or strips and their passage through the cutting area of the machine.
The devices disclosed therein are also characterized by the inclusion of a fixed "combing" means or "scraping" element which tends to prevent the collection of any material around the rotating spacer ring. The location of the fixed combing means at the lower or rear region of each spacer ring would prevent the collection of the strip or piece material at the backside of the spacer ring remote from the cutting area. However, as will be seen, the general shape and form of such combing means may not be satisfactory for the "combing" or "scraping" of pieces formed from tires because of the heat produced by friction between the pieces and the fixed combing means.
Another group of cutting or shredding machines also includes additional means for preventing the collection of pieces of material at the remote side of the cutting wheels themselves rather than simply at the remote or backside of the spacer ring. Such cutting or shredding machines are disclosed in U.S. Pat. No. 4,068,805; French Patent No. 45,173; and Japanese Patent Nos. 55-136597 and 63-232860. All of these machines apparently incorporate a solid comber block or backing member which occupies the space within the housing at the backside of both the rotating cutting wheels and the spacer rings therebetween. Such configurations will again tend to prevent most of the pieces or strips from being carried about the interior of the machine with the rotating cutting discs and spacers. To a greater or lesser degree, each of these prior art comber configurations will tend to prevent the collection of such pieces or strips in the region remote from the cutting area. However, as will be seen later, the particular configurations of the prior art combing devices aligned with the spacer rings do not entirely prevent the generation of undesired heat by the friction created between the pieces of tire and the fixed combing devices.
All of the U.S. and foreign patents mentioned hereinabove are incorporated by reference as if included in their entirety herein.